Research fellow at CERN in Geneva in (1958), research assistant at the
Max-Planck-Institute for Physics und Astrophysics in Munich (1959-62, 1963-65),
and research fellow at MIT in Cambridge (Mass.) (1962-63).

Habilitation 1961 at the University of Munich with a paper on Quantum Logic.

Since 1965 full professor for Theoretical Physics at the University of Cologne.
Dean of the Faculty for Mathematics and Science in 1968-69.
Rector of the University in 1970-71 (portrait).
Prorektor for Research in 1991-94.
Since 1995 retired (emeritus).

Main research fields: Foundations of Quantum Theory, Relativity Theory, Philosophy of Science and Logic.

Member of:

International Quantum Structures Association (IQSA)
(founding member, President in 1994-96).